separate two different commands in two lines
separate two different commands in two lines

In the doc senlin/doc/docbkx/README.rst, command
"cd senlin-admin mvn clean generate-sources" are two
different commands "cd senlin-admin" and "mvn clean generate-sources",
which should be in different lines.

Closes-Bug: 1550181
Change-Id: Ic213aa54d83b584f67911374abf6d26e500002e2

openstack/senlin,tengqm/senlin-container,openstack/senlin,tengqm/senlin-container,openstack/senlin,stackforge/senlin,stackforge/senlin